Electric propulsion systems are increasingly being used in the field of spatial propulsion, particularly for the steering and orbital control of spacecraft, and more specifically satellites. Indeed, the different available types of electric propulsion systems generally offer higher specific impulse than chemical propulsion systems, thus helping to reduce propellant consumption for the same manoeuvres, with a consequent increase in the service life and/or payload of the satellites.
Among the various types of electric propulsion systems, there are in particular those referred to as electrostatic propulsion systems, wherein the propellant fluid is ionized and directly accelerated by an electric field. The so-called Hall-effect propulsion systems fall in this category.
The electric propulsion systems are subjected to extreme thermal conditions, both when they are in operation (temperatures reach at least 300° C. for the coolest parts) or when they are off (since the electric propulsion systems are positioned on an outer side of satellites, they are in direct contact with cold space).
Since an electric propulsion system is generally qualified for a given range of temperatures, outside this range of temperatures, it may suffer from damage. It is therefore important to control the temperature of the electric propulsion system.
Currently, measuring equipment of the thermistor or thermocouple type, and heating equipment of the electric propulsion system, which can bear such extreme temperatures, are few in number, complex to implement, bulky, heavy and very expensive.
Existing solutions consist of positioning temperature sensors, such as thermistors or thermocouples, and heating equipment for the electric propulsion system, on a support structure linking the electric propulsion system to the satellite structure.
These solutions nevertheless have numerous drawbacks.
Firstly, the temperature sensors and heating equipment of the electric propulsion system are not fixed directly to said electric propulsion system, but via a support structure which has thermal insulation properties. The temperature is therefore measured very indirectly, and therefore, the temperature measured by the temperature sensors is not representative of the temperatures inside the electric propulsion system.
Secondly, as the exact temperature inside the electric propulsion system is not known, the electric propulsion system heating equipment is oversized, particularly to ensure that the electric propulsion system is kept hot enough when it is not running. Such electric propulsion system heating equipment is therefore very energy intensive.